This is installed in the liquid line of the system after the receiver. Construction is generally in the form of a tube which contains coarse and fine mesh filters. These prevent foreign matter such as dirt, metal filings and carbon sludge circulating with the refrigerant. The tube also contains a drying agent or dessicant which will absorb any moisture in the refrigerant (see Figure 89).

A burn-out drier is specifically intended for installation in both the liquid line and the suction line of a system following the replacement of a hermetic or semi-hermetic compressor in which the motor windings have burnt out. This type of filter drier has the extra ability to retain acids which could be present in the oil residue entrained in parts of the system.